Technical Field
This application generally relates to data storage, and more particularly to techniques used in connection with modeling or simulating a data storage system.
Description of Related Art
Computer systems may include different resources used by one or more host processors. Resources and host processors in a computer system may be interconnected by one or more communication connections. These resources may include, for example, data storage devices such as those included in the data storage systems manufactured by EMC Corporation. These data storage systems may be coupled to one or more host processors and provide storage services to each host processor. Multiple data storage systems from one or more different vendors may be connected and may provide common data storage for one or more host processors in a computer system.
A host processor may perform a variety of data processing tasks and operations using the data storage system. For example, a host processor may perform basic system I/O operations in connection with data requests, such as data read and write operations.
Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units, disk drives, and disk interface units. Such storage devices and data storage systems are provided, for example, by EMC Corporation of Hopkinton, Mass. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units, logical devices or logical volumes. The logical disk units may or may not correspond to the actual physical disk drives. Allowing multiple host systems to access the single storage device unit allows the host systems to share data stored therein.
Design objectives for data storage systems include cost, performance, and availability. Objectives typically include are a low cost per megabyte, a high I/O performance and low response time (RT), and high data availability. Availability is measured by the ability to access data. Often such data availability is provided by use of redundancy using well-known techniques such as mirroring, RAID protection and remote replication.
One problem encountered in the implementation of data storage systems concerns optimizing the storage capacity while maintaining the desired availability and reliability of the data through redundancy. It is important to allocate as closely as possible the right amount of storage capacity with going over or under significantly because of cost and necessity but this is a complex task. It has required great deal of skill and knowledge about computers, software applications such as databases, and the very specialized field of data storage. Such requisite abilities have long been expensive and difficult to access. There remains and probably will be an increasing demand for and corresponding scarcity of such skilled people.
Determining the size and number of disk array or other data storage system needed by a customer requires information about both space, traffic and a desired quality of service. It is not sufficient to size a solution simply based on the perceived quantity of capacity desired, such as the number of terabytes believed to be adequate. In addition to general capacity planning problems with data storage systems other complexities may arise. One such complexity arise when there is an interest in merging existing data storage systems with newer or fewer data storage systems. Such consolidation helps a customer reduce operating costs by decreasing the number of storage systems, and migrating the data to fewer and/or newer, larger capacity, more efficient storage systems. Consolidation may be of interest for some of the following reasons: saving footprint space; reducing the cost of utilities; simplifying management and reducing management costs; reducing hardware inventory costs; and upgrading to new technology. On the other hand there are costs associated with such a change and there is need for a simple tool to allow for the analysis of such a change and to determine an optimum solution, and in particular with regard to performance requirements and desired characteristics.
There is a long-felt need for a computer-based tool that would allow a straight-forward non-complex way to allocate proper storage capacity while balancing cost, growth plans, workload, and performance requirements and further if such a tool would be useful for analyzing consolidation or merging operations along with simulation or modeling of different aspects of a data storage system.